1. Field of the Invention
The present invention relates to a thermoplastic resin which gives a molded article having good impact resistance, flexural modulus, chemical resistance, heat resistance and dimensional stability.
2. Description of the Related Art
ABS resins have well balanced physical properties and dimensional stability and are used in various fields. However, if some corrosive materials such as gasoline, brake fluids or rust preventive oils adhere to the ABS resin, the resin tends to crack. Therefore, it has been desired for a long time to improve the resistance of ABS resin against various chemical materials.
As a resin having good chemical resistance, a saturated polyester resin is known, but has inferior impact resistance, in particular notched Izod impact strength and, in addition, poor dimensional stability.
Japanese Patent Kokai Publication No. 219362/1984 proposes the addition of a small amount of the saturated polyester resin to a specific ABS resin composition comprising a styrene-acrylonitrile base copolymer having a specific intrinsic viscosity to provide a resin composition having improved chemical resistance, dimensional stability and weld strength without deteriorating good physical properties of the ABS resin. However, the obtained resin composition is not necessarily satisfactory in heat resistance and the balance between flexural modulus and impact resistance. To improve only heat resistance, Japanese Patent Kokai Publication No. 11347/1984 proposes a composition comprising the saturated polyester resin and an .alpha.-methylstyrene-methacrylate copolymer which is optionally reinforced with a rubber. But, such resin composition is inferior in the balance between flexural modulus and impact resistance. In addition, silver streaks are generated on the molded article surfaces. Then, such resin composition is not a practically attractive material.